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2. Description of the event
In this evaluation we will focus on the rainfall over three periods: 5-day rainfall 13-18 December plus 1-day rainfall on 13 and 17 December. The focus region is the coastline of Queensland (land points inside 15.5S - 17.5S, 145E- 146E).
The plots below show analyses of MSLP and 6 hour rainfall from 11 December 00UTC to 18 December 00UTC, every 12th hour. TC Jasper made landfall on 13 December, but later stalled over Queensland, while the rainfall continued. On 17 December the rainfall intensified.
3. Predictability
3.1 Data assimilation
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The plot below shows the forecast evolution plot for 5-day precipitation (13 December 00UTC - 18 December 00UTC) in land-points inside the box outlined in the plots above. Concatenated 6-hour forecasts - green dot, ENS control –red, ENS blue box-and-whisker, Model climate – cyan box-and-whisker. Ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1800 forecasts. (Climate to be added)
The predictability for this period to be wetter than normal in the region was relatively good with a clear signal from 5 December and onwards. This coinside with the genesis of TC Jasper.
The plots below shows EFI and SOT for 1-day precipitation (13 December 00UTC - 14 December 00UTC) from different initial dates.
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The plot below shows the forecast evolution plot for 1-day precipitation (13 December 00UTC) in land-points inside the box outlined in the plots above. Concatenated 6-hour forecasts - green dot, ENS control –red, ENS blue box-and-whisker, Model climate – cyan box-and-whisker. Ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1800 forecasts.(Climate to be added)
The problem for the forecast on 13 December is obvious here, and is probably related to the data assimilation issue discussed in Section 3.1.
The plots below shows EFI and SOT for 1-day precipitation (17 December 00UTC - 18 December 00UTC) from different initial dates.
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The plot below shows the forecast evolution plot for 1-day precipitation (17 December 00UTC) in land-points inside the box outlined in the plots above. Concatenated 6-hour forecasts - green dot, ENS control –red, ENS blue box-and-whisker, Model climate – cyan box-and-whisker. Ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1800 forecasts.(Climate to be added)
The predictability of this phase seem to have been relatively low as the signal started to appear on 14 December, probably related to the propagation of the tropical cyclone (see below).
The plots below show the tropical cyclone track for TC Jasper for the operational ECMWF forecasts from 15 December 00UTC (first plot) to 5 December 00UTC (last plot). The symbols shows the position on 15 December 00UTC (hourglass for BestTrack). HRES (red), ENS CF (blue), ENS PF (grey) and BestTrack (black).
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